﻿Module Module1
  Sub Main()
    Console.WriteLine(Numero(7))
    Console.WriteLine(Numero())
    Console.ReadLine()
  End Sub

  Private Function _
           Numero(Optional ByVal n _
           As Integer = -1) As String
    If n = -1 Then
      Return "Opzionale"
    Else
      Return CType(n, String)
    End If
  End Function
End Module
